Rolling of stranded electrical conductors



Oct. 30, 1934. ROHS 1,979,013

ROLLING OF STRANDED ELECTRICAL CIONDU'STORSv Filed April 29, 1933 H-Rohs mvelvToK BY: WW

Patented Oct. 30, 1934 UNITED STATES PATENT OFFICE ROLLING F STRANDED ELECTRICAL CONDUCTORS many Application April 29,-1933, Serial No. 668,640 In Czechoslovakia May 5, 1932 1 Claim. (Cl. 117-16) It is known in the case of stranded electrical conductors of non-circular cross-section having a straight-line conductor axis and peripheral lines running parallel to the said axis to subject the said conductors to a subsequent rolling in order to obtain a better filling factor for the copper conductor, that is to say a greater ratio of section of solid copper to the total crosssection of the stranded conductor. It has also been proposed to effect a subsequent rolling of stranded electrical conductors of non-circular cross-section, the individual wires of which are stranded together around a straight line con ductor axis in such a manner that the non-cirl5 cular cross-section of the conductor has a uniform twist around the conductor axis. It is further known in the case of stranded conductors of circular cross-section to produce a sector shape and uniform twist of the cross-section around the axis of the conductor by subsequent rolling.

The subsequent rolling of the conductors hardens the copper wires which were previously soft and the rolled conductor receives a twisting tension which renders the subsequent treatment of these conductors very diflicult. Those sectorshaped conductors which have been rolled into the said uniformly twisted shape from strands of circular cross-section receive an especially great tension which causes them to tend to spring back.

In order to destroy the said twisting tension, according to the invention the rolled conductors, after they have left the pressing rolls, are twisted with a shorter pitch than that which would be required for the stranding of the insulated conductors into a multi-core cable in the case of soft material which has no tendency to spring back. This may be attained by the provision of a second pair of rolls beyond the actual justed that the rolled conductor, in the interval between the actual pressing rolls and the second pair of rolls, is positively twisted with a shorter pitch than that resulting from the ratio of a single revolution of the roller casing of the first pair of rolls around the axis of the conductor to the delivery speed of the conductor caused by the take-oi drum of the machine.

The conductor is thereby stressed slightly beyond its elastic limit, thus losing its tendency to spring back so that the conductor no longer tends to twist, being entirely free from any tension and thus enabling the conductors to be easily laid to form the complete cable.

A third pair of rolls may be provided beyond pressing rolls. The second pair of rolls is so ad-- the-second pair, in order in press again into the right position the wires of the conductor which, during the passage through the first pair of rolls, have been deformed and which have been slight- 1y canted by the shorter twisting of the whole of the conductor between the first and the second pair of rolls. Instead of the two pairs of rolls, use may be made simply of pairs of guiding rollers formed with corresponding grooves. The two last pairs of rolls, which rotate with the same speed as the first pair of rolls around the longitudinal axis of the conductor to be rolled may be mounted on separate stands and be provided with separate drives. Further, all the three pairs of rolls or only individual pairs may be provided with one drive for the rolls.

Figs. 1-4 of the accompanying drawing illustrate, by way of example, two different rolling arrangements according to the present invention for compensating the tensions to which the tendency to spring back is to be attributed and which are caused by the rolling of a conductor,

Figs. 1 and 2 showing in elevation and plan view one form of construction and Figs. 3 and 4 a sectional elevation and a plan view of the second form of construction.

Referring to the arrangement illustrated in Figs. 1 and 2, 1, 2 and 3 are three pairs of rolls, the housings 4, 5 and 6 of which are mounted with their hollow shafts in the stands 7, 8 and 9 respectively. The drive of the roll housings is effected through the intermediary of the pinions 10, 11 and 12 which are secured to the hollow shafts of the corresponding roll housings. All the three pairs of rolls nm at one and the same speed around the axis of the conductor, being driven from a suitable shaft of the machine in which the arrangement of rolls is embodied. The three rolling devices are secured to a table 13. The pairs of rolls 1, 2 and 3 are rotatably mounted in corresponding roll housings 4, 5 and 6, the rotation taking place around the longitudinal axis of .the conductor to be rolled and the pairs of rolls being capable of being fixed in position, so that the grooves 14, 15 and 16 provided in the pairs of rolls can be easily set to the pitch of the conductor.

The pairs of rolls 1 and 2 are so adjusted that wires of the conductor which, during the passage through the first pair of rolls, have been deformed and which have been slightly canted along the shorter pitch between the-pairs of rolls 1 and 2.

By making the pair of rolls 3 capable of adjustment around the axis of the conductor, also this pair of rolls can be easily adapted to the pitch of the conductor. The three pairs of rolls 1, 2 and 3 can be adjusted in their relative positions by a displacement of the stands 7, 8 and 9 along the table 13.

In the form of construction illustrated in Figs. 3 and l, l7, l8 and 19 are the pairs of rolls; the roll housingt20 of the first pair of rolls 1'? is mounted in the bearing stand 21. The drive is effected by means of the pinion 22, which is secured to the hollow shaft of the roll casing 20. The disc 23 is also secured to the said hollow shaft; the disc being provided with two guiding rods 24, which carry two displaceable sliding members 25, which can be fixed in position and in which the supports 26 of the pairs of rolls l8 and 19 are inserted in such a manner that they can be rotated and be fixed in position. This makes it possible for the distance between the pairs of rolls 17, 18 and 19 to be adjusted and the pairs of rolls 18 and 19 to be rotated around the axis of the conductor to be rolled in order easily to adapt the individual pairs of rolls to the pitch of the conductor.

What I claim is:-

A method of producing rolled, stranded, electrical conductors of non-circular cross-section having a straight line conductor axis and a uni-. form twist of cross-section around the axis of the conductor, consisting in that in order to destroy the twisting tension of the conductor which is produced during the rolling of the twisted conductor the rolled conductors, after they have left the press rolls, are twisted with a shorter pitch than that required for the stranding of the insulated conductors into a multi-core cable when use is made of a soft material which has not a tendency to spring back.

ADOLF ROI-IS.

Hill 

